This application claims benefit of Japanese Patent Application No. 2002-152126 filed on May 27, 2002, the contents of which are incorporated by the reference.
The present invention relates to improvements in portable data terminal unit capable of direct communication with other terminal units without network, which is different from the usual portable telephone set having a main communication function part including a communication function via a network.
Up to date, a file transfer system has been proposed, which permits direct file transfer between portable data terminals without agency of any file server and also permits file transfer request operation input on the sole telephone set side (Japanese Patent Laid-Open No. 2001-128242). This proposal concerns a system for transmitting (i.e., down-loading) files in remote places to a near-by portable data terminal or personal computer by using a portable telephone set. More specifically, a portable telephone set having a wireless function for portable telephone communication and a separate close distance wireless communication function, is utilized for the transmission (i.e., down-loading) of files.
In the inter-portable telephone terminal file transmission system, each portable telephone terminal internally includes a portable telephone file reception application means for making list request and transmitting selected input, and also a transmission side portable data terminal is provided, which is started by a reception side request to transmit list and subject file. The system is thought to provide such effects that it is possible to make direct inter-portable data terminal file transfer without file server which is capable of being commonly used and also improve the operability in that request operations are made from the telephone terminal side alone.
A wireless communication system is also proposed, which comprises a wireless communication means for directly transmitting own position data of GPS (global positioning system) representing the present position of a wireless communication unit to a measurement subject unit by wireless communication based on Bluetooth, and a computing means for computing, after reception of a signal of response to the own position data signal returned from the measurement subject unit, the distance of the measurement subject unit from the present position on the basis of the response signal and own position data signal (Japanese Patent Laid-Open 2001-359143). This system is thought to be able to readily detect the distance and position relation of the measurement subject by directly exchanging measurement signal and response signal as subject of measurement without agency of any base station.
The Bluetooth represents close distance wireless data communication standards which are provided by Bluetooth SIG (Special Interest Group) as a standardizing group. The standards use a spread spectrum communication system based on frequency hopping system, in which 79 channels of a bandwidth of 1 MHz are set in an ISM Band (Industrial Scientific and Medical Equipment Band) of a bandwidth of 2.4 GHz for switching at a rate of 1,600 times a second. The system permits the data communication at a close distance of about 10 m with a data transmission rate of about 1 Mbit/s(actually 721 Kbits/s).
In the system proposed in Japanese Patent Laid-Open No. 2001-128242, it is necessary to provide, in each portable telephone terminal, the portable telephone file reception application means for making list request and transmitting the selected input and also provide a transmission side portable data terminal for transmitting list and subject file, leading to complicated construction.
The proposal in the Japanese Patent Laid-Open No. 2001-128242, on the other hand, can not permit direct transmission of voice and data between two portable telephone terminals by using the Bluetooth.
Furthermore, as is well known in the art, when making search of other terminals by using the Bluetooth, all terminals able to make communication are recognized, and it is thus difficult to limit the opposite side of communication to only terminals as desired by the user without provision of any particular means. Also, when it is desired to transmit data to sole wireless data terminal present in the neighborhood by using such close distance wireless communication function as the Bluetooth and infrared communication, a cumbersome operation of matching on both the transmitting and receiving sides is necessary.
Particularly, in the case when transmission data represents images picked up by an imaging device, there has been no effective means of satisfying, in a simple operation, needs for transmitting the data to a plurality of particular terminals present in the neighborhood.